TW201810701A - Perovskite solar cell and manufacturing method thereof - Google Patents

Abstract

The present invention provides a perovskite solar cell comprising a layer of perovskite material having a first surface and a second surface opposite to each other; an electron transport layer disposed on the first surface; and a gold nickel An oxide layer disposed on the second surface. The invention also provides a method for manufacturing a perovskite solar cell, comprising: providing a transparent substrate; forming a gold-nickel oxide layer on the transparent substrate; and forming a layer of perovskite material on the gold-nickel oxide layer .

Description

Perovskite solar cell and manufacturing method thereof

The present invention relates to a perovskite solar cell and a method of manufacturing the same, and more particularly to a perovskite solar cell using gold nickel oxide as a transparent electrode layer and a method of manufacturing the same.

Perovskite materials have excellent advantages for applications on solar cells, such as high carrier mobility, high carrier diffusion distance, high absorption coefficient and other characteristics are suitable for the production of high efficiency solar cells. Another advantage is that the material cost is low and the process is simple. The ultra-thin light absorbing layer can be fabricated by a simple wet coating process and has high photoelectric conversion efficiency. Its power generation cost is estimated to be only one-fifth to one-quarter of the crystal battery. Due to its high photoelectric conversion efficiency, low manufacturing cost and simple process, it has caused considerable impact in the technical field of solar cells. But so far, the technology of perovskite solar cells is not yet mature, and many basic research is rapidly expanding, which has led to a large amount of research and development by research units in various countries. In recent years, the efficiency of perovskite solar cells has progressed very rapidly, and the photoelectric conversion efficiency has reached 18%.

At present, most of the published literature mostly uses a transparent conductive oxide (TCO), which is first etched by laser etching or exposure on a cell structure, and a perovskite material and an n-type semiconductor metal oxide (n- Type metal oxide) Suitable hole transport materials (HTM) are used to make perovskite solar cells, which are commonly used n-type semiconductor oxide/perovskite/hole transfer materials (n-type metal oxide/perovskite/ Stack structure of hole transport materials). The n-type semiconductor metal oxide and the hole transporting material are respectively used as a transport layer of electrons and holes, and can selectively assist electron-hole pairs extracted and separated from the perovskite material. In addition, for a solar cell of an inverted structure, it is common practice to coat a glass substrate/indium tin oxide (glass/ITO) with a layer of PEDOT:PSS(poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate), and then The perovskite material is grown on a hole transport material and fabricated into a solar cell with a suitable electron transport material.

PEDOT: The highest occupied molecular orbital level (HOMO) of PSS is 5.1 eV, which can be used as a hole transport material for perovskite materials. In addition, PEDOT:PSS can also improve the surface properties of ITO to facilitate the growth of subsequent perovskite materials. However, since PEDOT:PSS is an acidic substance (pH=1.2) and hygroscopic, it is easy to cause corrosion damage of ITO, and the indium (Indium, In) in ITO diffuses into the active layer, which makes the photoelectric characteristics of the element. decline. In addition, organic materials are generally not conducive to long-term operation under ultraviolet light, while solar cells require long-term component stability to increase their useful life.

Therefore, it is necessary to provide a perovskite solar cell and a method of manufacturing the same to solve the problems in the conventional technology.

The main object of the present invention is to provide a perovskite solar cell which utilizes a gold-nickel oxide layer having a neutral acid value, which can have a relatively good transmittance and can be used as a hole. The transport material is bonded directly to the layer of perovskite material and serves as a transparent electrode. Therefore, the perovskite solar cell can eliminate the use of the organic hole transport layer, has a simple structure and high component stability, can improve the life of the component, reduce the consumption cost, and improves the applicability of the perovskite solar cell.

Another object of the present invention is to provide a method for manufacturing a perovskite solar cell, which can form the gold nickel oxide layer by a quick and simple thermal annealing process, and omits the formation of the conventional organic hole transport material and the transparent conductive film ITO. Steps to simplify the manufacturing process.

To achieve the above objective, an embodiment of the present invention provides a perovskite solar cell comprising: a layer of perovskite material, comprising a first surface and a second surface opposite to each other; an electron transport layer, configured And on the first surface; and a gold-nickel oxide layer disposed on the second surface.

In an embodiment of the invention, the perovskite layer has a molecular formula of CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbI _x Cl _3-x or HC(NH ₂ ) ₂ PbI ₃ .

In an embodiment of the present invention, the gold-nickel oxide layer comprises gold (Au) embedded in the network structure of nickel oxide (NiO _X) in.

In an embodiment of the invention, the perovskite solar cell further comprises a transparent substrate, and the gold nickel oxide layer is disposed on a surface of the transparent substrate.

In an embodiment of the invention, the transparent substrate is a glass substrate.

In an embodiment of the invention, the gold nickel oxide layer has a thickness of 50 nm or less.

In an embodiment of the invention, the electron transport layer comprises fullerene, ZnO, TiO ₂ or [6.6]-phenyl-C61-butyric acid methyl ester (PCBM, [6,6]-phenyl-C61-butyric Acid methyl ester).

In order to achieve the above object, another embodiment of the present invention provides a method of manufacturing a perovskite solar cell, comprising the steps of: providing a transparent substrate; forming a gold-nickel oxide layer on the transparent substrate; and forming a A layer of perovskite material is layered on the gold nickel oxide layer.

In an embodiment of the invention, the gold-nickel oxide layer is formed by: forming a nickel (Ni) layer on the transparent substrate; forming a gold (Au) layer on the nickel layer; The transparent substrate, the nickel layer and the gold layer are subjected to a thermal annealing treatment in oxygen to form a gold (Au) network structure embedded in nickel oxide (NiO _X ).

In an embodiment of the invention, the transparent substrate is a glass substrate, and the temperature of the thermal annealing treatment is 350 to 550 °C.

In an embodiment of the invention, the nickel layer and the gold layer are formed by an electron beam method.

In an embodiment of the invention, both the thickness of the nickel layer and the thickness of the gold layer are less than 20 nanometers.

In an embodiment of the invention, the perovskite layer is an organic lead iodine compound having the formula CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbI _x Cl _3-x or HC(NH ₂ ) ₂ PbI ₃ .

In an embodiment of the invention, after the layer of the perovskite material is formed, the method further comprises the step of forming an electron transport layer on the layer of the perovskite material.

In an embodiment of the invention, the electron transport layer is fullerene, ZnO, TiO2 or [6.6]-phenyl-C61-butyric acid methyl ester.

10‧‧‧Perovskite solar cells

11‧‧‧Perovskite material layer

12‧‧‧ Gold Nickel Oxide Layer

13‧‧‧Electronic transport layer

14‧‧‧Transparent substrate

14'‧‧‧ glass substrate

15‧‧‧Electronic buffer layer

16‧‧‧Metal electrodes

Fig. 1 is a schematic view showing the structure of a perovskite solar cell according to an embodiment of the present invention.

2A-2C: Formation mechanism of a gold-nickel oxide layer according to an embodiment of the present invention.

3A ~ 3B of FIG: a scanning electron microscope (SEM) observation of the gold-nickel oxide layer according to an embodiment of the present invention: the surface and a cross-sectional structure (Au NiO _X) a.

Figure 4: shows the change in the transmittance of the gold-nickel oxide layer of the control group and the experimental group 1 to 5 for different wavelengths of light.

Figure 5: Trend diagram of the work function of the gold-nickel oxide layer in the experimental group 1~4.

The above and other objects, features and advantages of the present invention will become more <RTIgt; Furthermore, the directional terms mentioned in the present invention, such as upper, lower, top, bottom, front, rear, left, right, inner, outer, side, surrounding, central, horizontal, horizontal, vertical, longitudinal, axial, Radial, uppermost or lowermost, etc., only refer to the direction of the additional schema. In addition, the singular forms "a", "the" The range of values (such as 10% to 11% of A) includes upper and lower limits (ie, 10% ≦A ≦ 11%) unless otherwise specified; if the value range does not define a lower limit (such as less than 0.2% B) , or B) below 0.2%, the lower limit may be 0 (ie 0% ≦ B ≦ 0.2%). The above terms are used to illustrate and understand the present invention and are not intended to limit the invention.

Referring to FIG. 1 , an embodiment of the present invention provides a perovskite solar cell 10 , which mainly comprises a perovskite material layer 11 including a first surface and a second surface opposite to each other; An electron transport layer 13 disposed on the first surface; and a gold-nickel oxide layer 12 disposed on the second surface. The perovskite solar cell 10 is mainly a layer A stacked structure with substantially flat junctions between the layers.

The perovskite material layer 11 is an organic-inorganic composite photosensitive material, preferably having a molecular formula of CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbI _x Cl _3-x or HC(NH ₂ ) ₂ PbI ₃ . The gold-nickel oxide layer 12 has light transmissivity, and allows sunlight to pass through the layer and is absorbed by the perovskite material layer 11 to generate electrons and holes. The gold nickel oxide layer 12 is a composite layer comprising gold and nickel oxide, and the gold nickel oxide layer 12 may be embedded in nickel oxide (NiO _X ) in a network structure containing gold (Au). . The gold-nickel oxide layer 12 has a thickness of 50 nm or less, and may be, for example, 10 to 50 nm, preferably 20 to 45 nm, such as 25, 30 or 40 nm, but is not limited thereto.

Preferably, the perovskite solar cell 10 further comprises a transparent substrate 14 such that the gold nickel oxide layer 12 can be disposed on a surface of the transparent substrate 14, that is, the gold nickel oxide layer 12 is sandwiched. It is disposed between the transparent substrate 14 and the perovskite material layer 11. The gold (Au) network structure of the gold nickel oxide layer 12 is embedded in nickel oxide (NiO _X ), and the nickel oxide (NiO _X ) is adjacent to the perovskite material layer 11; and the gold nickel oxide layer The network structure of gold (Au) of 12 is relatively close to the transparent substrate 14 (i.e., relatively far from the layer 11 of the perovskite material). The transparent substrate 14 can be, for example, a glass substrate.

Further, electron transport materials usable for perovskite solar cells, such as fullerene, ZnO, TiO ₂ or [6.6]-phenyl-C61-butyric acid methyl ester (PCBM, [6, 6]-phenyl), are generally known. -C61-butyric acid methyl ester) can be used as the electron transport layer 13.

Furthermore, as shown in FIG. 1, the perovskite solar cell 10 generally also includes an electron buffer layer 15 and a metal electrode 16. The electronic buffer layer 15 is disposed on a surface of the electron transport layer 13 and may be, for example, a BCP (bathocuproine). However, the present invention is not limited thereto. Generally, an electron transport material commonly used in solar cells can replace the BCP. The metal electrode 16 can be disposed on the electron The buffer layer 15 serves as a cathode; and is additionally disposed on the gold nickel oxide layer 12 as an anode. The metal electrode 16 may be, for example, an aluminum metal electrode, but is not limited thereto. The sunlight can enter the internal structure of the perovskite solar cell 10 from the gold nickel oxide layer 12 and the transparent substrate 14, and the voltage tendency of the electron hole is generated after photoelectric conversion. Then, the metal electrode 16 can be disposed. A proper transfer loop conducts its current.

Another embodiment of the present invention provides a method of fabricating a perovskite solar cell 10, which mainly includes the steps of: (1) providing a transparent substrate 14; and (2) forming a gold-nickel oxide layer 12 on the transparent substrate 14. And (3) forming a layer 11 of perovskite material on the gold-nickel oxide layer 12.

In the step (1), the transparent substrate 14 is a high temperature resistant transparent substrate, preferably a glass substrate, but is not limited thereto.

In the step (2), the gold nickel oxide layer 12 can be formed, for example, by the step of: (2a) forming a nickel (Ni) layer on the transparent substrate 14; (2b) forming a gold (Au). a layer on the nickel layer; and (2c) subjecting the transparent substrate 14, the nickel layer and the gold layer to a thermal annealing treatment in oxygen to form a gold (Au) network structure embedded in the nickel oxide . In this step, the temperature of the thermal annealing treatment may be 350 to 550 ° C, and may be, for example, 350, 450, 500 or 550 ° C, but is not limited thereto. The time of the thermal annealing treatment may be 3 to 10 minutes, for example, 3, 4, 5, 6, 7, 9, or 10 minutes, but is not limited thereto. The nickel layer and the gold layer can be formed by an electron beam method. The thickness of the nickel layer and the thickness of the gold layer are both less than 20 nm, and may be, for example, 7, 10, 15, or 20 nm, but is not limited thereto. Preferably, the nickel layer has a thickness of 10 nm while the gold layer has a thickness of 5 or 7 nm.

In the step (3), the perovskite material layer 11 is an organic lead iodine compound, and its molecular formula may be, for example, CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbI _x Cl _3-x or HC(NH ₂ ). ₂ PbI ₃ . In this step, the perovskite material layer 11 can be formed by first preparing an organic lead iodine compound solution, and then coating the gold nickel oxide layer 12 at 1000 rpm for 20 seconds; The organic lead iodine compound solution was evenly distributed on the gold nickel oxide layer 12 to form an organic lead iodine film by forming the organic lead iodine film evenly at a speed of 25 rpm for 25 seconds without adding a solution; then, maintaining 4000 rpm and The organic lead iodine film was blown with nitrogen for 35 seconds; finally, the organic lead iodine film was thermally annealed at 100 ° C for 10 minutes.

In addition, after the formation of the perovskite material layer 11, a further step may be further included: forming an electron transport layer 13 on the perovskite material layer 11, wherein the electron transport layer 13 may be selected from fullerene, ZnO, TiO ₂ or PCBM.

Please refer to FIGS. 2A to 2C for explaining the formation mechanism of the gold-nickel oxide layer 12. As shown in FIG. 2A, the nickel layer and the gold layer are sequentially formed on the transparent substrate 14 by electron beam method. Next, as shown in FIG. 2B, when the thermal annealing treatment is performed in an environment where oxygen (O ₂ ) is sufficient, the gold layer and the nickel layer diffuse, partially from the metal grain boundary of the gold. The spilled nickel begins to react with oxygen to form nickel oxide (NiO _X ). As more and more nickel oxide continues to accumulate at the grain boundaries of the gold, gold that is not oxidized is pushed and deposited on the transparent substrate 14. Finally, a network structure in which the gold is formed as shown in Fig. 2C is embedded in the nickel oxide.

The present invention further provides actual test data and analysis to verify the structure and efficiency of the perovskite solar cell of the above-described embodiments of the present invention.

Please refer to Figures 3A and 3B, which show the surface and cross-sectional structure of the formed gold-nickel oxide layer (Au:NiO _X ) observed by scanning electron microscopy (SEM) after thermal annealing at 500 ° C for 5 minutes. . It can be seen from Fig. 3A that the surface morphology already has a gold network structure and an island structure in the nickel oxide layer, and from Fig. 3B, it can be seen that the nickel oxide (NiO _X ) formed by the lower layer of nickel is gold. Push onto the glass substrate 14'. In the SEM image, the portion of nickel oxide (NiO _X ) is dark gray (black), and the brighter portion is gold (Au).

Please refer to Table 1 below for comparison of the photoelectric characteristics of the gold-nickel oxide layer formed by thermal annealing at different temperatures for 5 minutes, and using ITO/PEDOT:PSS for existing perovskite solar cells. As a control group. Among them, 7Au:NiO _X represents a gold nickel oxide layer formed by thermal annealing of a 7 nm thick gold layer and a 10 nm thick nickel layer, and 5Au:NiO _X is a 5 nm thick gold layer and A gold nickel oxide layer formed by thermal annealing after a 10 nm thick nickel layer.

It can be seen from Table 1 that the gold layer and the nickel layer having the same thickness in the experimental groups 1 to 4 are At different temperatures, the photoelectric properties of the formed gold-nickel oxide layer are also greatly different. The gold-nickel oxide layer obtained by thermal annealing of the experimental group 3 at 500 ° C has an optimum photoelectric conversion efficiency of about 10.24%. It is quite close to the existing transparent electrode ITO and hole transport layer PEDOT:PSS.

Please continue to refer to Fig. 4, which shows the change in the transmittance of the gold nickel oxide layer of the above control group and the experimental group 1 to 5. In addition, the penetration rates of the gold layer and the nickel layer before the thermal annealing treatment were measured by the experimental group 1 for comparison. It can be seen from Fig. 4 that after the thermal annealing treatment, the gold layer and the nickel layer (unannealed) which are originally opaque can be converted into the gold nickel oxide layer having a transmittance of about 40% in the experimental group 1, with An increase in the annealing temperature increases the penetration rate to approximately 70% (experimental group 3 to 5). In addition, from the experimental group 3 and the experimental group 5, it is known that the gold and nickel layers of different thicknesses are subjected to thermal annealing at 500 ° C, respectively, and the gold nickel oxide formed by the 5 nm gold layer and the 10 nm nickel layer of the experimental group 5 is oxidized. The layer has a higher penetration rate and can be increased by about 10% compared to the experimental group 3.

Please continue to refer to FIG. 5, which shows the change in work function of the above experimental groups 1 to 4. As can be seen from Fig. 5, as the thermal annealing temperature rises from 350 ° C to 550 ° C, the work function also rises, about 5.25 eV at 500 ° C.

According to the perovskite solar cell of the present invention and the method of manufacturing the same, the gold nickel oxide layer can have a relatively good light transmittance, up to about 70% after thermal annealing at 500 ° C, and has a perovskite phase The matched work function is about 5.25 eV because the gold nickel oxide layer contains NiO _X , which has a work function matching the perovskite material of 5.4 eV, which is 5.1 eV compared to the PEDOT:PSS work function due to The hole has less energy loss when it is transmitted, and is more suitable for extraction of holes, and has chemical stability and electron blocking ability. Furthermore, although the hole transport material NiO _X is very suitable as a hole transport material for a perovskite solar cell, the electrical characteristics of NiO _{X are} poor, so the present invention grows Ni/Au double by electron beam on a glass substrate. The layer structure is then annealed at high temperature to form Au:NiO _X , which can replace the traditional ITO as a transparent electrode, and does not need to use a hole transport material, and can form a fairly good heterojunction directly with the perovskite material layer.

The present invention has been disclosed in its preferred embodiments, and is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

Claims (15)

A perovskite solar cell comprising: a layer of perovskite material comprising a first surface and a second surface opposite to each other; an electron transport layer disposed on the first surface; and a gold nickel oxide a layer disposed on the second surface. The perovskite solar cell according to claim 1, wherein the perovskite material layer has a molecular formula of CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbIxCl _3-x or HC(NH ₂ ) ₂ PbI ₃ . The perovskite solar cell according to claim 1, wherein the gold nickel oxide layer comprises a network structure of gold (Au) embedded in nickel oxide (NiO _X ). The perovskite solar cell of claim 1, wherein the perovskite solar cell further comprises a transparent substrate, and the gold nickel oxide layer is disposed on a surface of the transparent substrate. The perovskite solar cell of claim 4, wherein the transparent substrate is a glass substrate. The perovskite solar cell of claim 1, wherein the gold nickel oxide layer has a thickness of 50 nm or less. The perovskite solar cell of claim 1, wherein the electron transporting layer is fullerene, ZnO, TiO ₂ or [6.6]-phenyl-C61-butyric acid methyl ester. A method for manufacturing a perovskite solar cell, comprising the steps of: providing a transparent substrate; forming a gold-nickel oxide layer on the transparent substrate; A layer of perovskite material is formed on the gold nickel oxide layer. The method for manufacturing a perovskite solar cell according to claim 8, wherein the gold nickel oxide layer is formed by: forming a nickel (Ni) layer on the transparent substrate; forming a gold ( Au) is layered on the nickel layer; the transparent substrate, the nickel layer and the gold layer are thermally annealed in oxygen to form a gold (Au) network structure embedded in the nickel oxide (NiO _X ) . The method of manufacturing a perovskite solar cell according to claim 9, wherein the transparent substrate is a glass substrate, and the temperature of the thermal annealing treatment is 350 to 550 °C. The method for producing a perovskite solar cell according to claim 9, wherein the nickel layer and the gold layer are formed by an electron beam method. The method for producing a perovskite solar cell according to claim 9, wherein the thickness of the nickel layer and the thickness of the gold layer are both less than 20 nm. The method for manufacturing a perovskite solar cell according to claim 8, wherein the perovskite material layer is an organic lead iodine compound having a molecular formula of CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbI _x Cl _3-x , HC(NH ₂ ) ₂ PbI ₃ . The method for manufacturing a perovskite solar cell according to claim 8, wherein after forming the layer of the perovskite material, the method further comprises the step of forming an electron transport layer on the layer of the perovskite material. The method for producing a solar cell according to claim 14, wherein the electron transporting layer is fullerene, ZnO, TiO ₂ or [6.6]-phenyl-C61-butyric acid methyl ester.